Aspen 1977 Super Six vacuum issues

1337m4723

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Hi Guys,

I am back again needing some answers.

My Super Six has some issues containing the carburetor and the vacuum system.

My first question is if I am thinking correctly: when the engine is cold and I am driving, it often dies recently.
I could recreate the problem yesterday, but only when it's cold:
- I hold the throttle as if I were driving steadily.
- Then I take off the gas as if I have to stop at an intersection.
- Then accelerate to start driving again. --> The engine dies and sounds like it has choked/hiccupped.
- When the engine warmed up, I could treat it with different throttle positions in a quick change and it did not die. Even when using the brakes and giving it a lot of throttle ind R or D.

My Idea: the carburetor throttle bearing is worn. When heated, the bearing fits again and the throttle function is back to normal.
Is this plausible? I am not a learned mechanic, so maybe this question is nonsense... But maybe you can understand what I am thinking about.

My second question is: I think the vacuum system has some issues. Idling is not really nice like the engine does not run "round".
I was searching for affordable spare-parts.
Do you know where vacuum parts are available? I don't necessarily need NOS parts. I would be happy with remanufactured Asian products or something similar.

- I blieve the vacuum solenoid valve is leaking. Is there a spare part available?
- I'd like to replace some vacuum-hoses...(my engine still has all original hoses I guess.)
- Is there a spare part for the Vacuum amplifier? (I don't know if this is really necessary...)

Maybe you can give me a hint if there are shops for those parts.. Rockauto has many parts, but not everything.

Best greetings from hanover (Germany)
Matze

IMG_20170827_175613_1.jpg
 

69-

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Hi Matze,

I'd first replace all old vacuum lines. Normal and locally available lines are perfectly ok.
The I'd check with a handheld gauge connected to manifold vacuum the vac level and impact of different driving situations. Take a loong line to the inside with the gauge right next to you.

There are some good sites available showing possible problems based on the vac readings.

Also, old fuel lines (Rubber Parts) can be a culprit. I replaced all of them as well. :)

That's what I would do before buying replacement parts.
 

1337m4723

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Hi 69- :)

Thank you for your response :)

Good to know, that other lines will fit as well! There are some "special" lines with stock connectors why I am a bit careful which line will work...
But what you write sounds like hoped, that every kind of vacuum hose can be used.

Good tipp with the gauge. Can I connect that thing at the same line as the brake booster and the vaccum amplifier? (they are are conencted to the vacuum manifold with a T-piece which has two more exits available with rubber plugs on it)

That could help to search for the vaccum problem I think.

For the carburetor issue I have the suspucion that the problem is not related to fuel or vacuum. :(
 

69-

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The tee is perfect for the gauge.

Re carburater throttle bushings. Yes, the could wear out and yes, thats air you dont want. Easy test: grab the throttle lever and try to move it up-down, best with air filter off, of course :).

If it is moving too much, you could get a new bushing in, but last time I had that done by a shop was in 2013. Could send you the contacts, it is in Germany, close to the border to the Netherlands. But I dont know if they are still in business.
 

Aspen500

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About the vacuum amplifier. It's for the EGR system and isn't vital, unless you have emission tests in where you live. It boosts the weak vacuum signal from the ported EGR hose from the carb to a higher vacuum signal that can open the EGR valve. Of course, if it leaks internally, you'd have a vacuum leak. They don't appear to be listed anymore aftermarket but I do see them on Ebay quite often.

Check the choke operation. If it only happens on a cold engine, it's possible the choke is opening too soon, and quickly opening the throttle causes an extreme lean condition and engine "cough" or stall. I only say that since you said it's fine with the engine warm. Worth a look anyways.

Some throttle shaft play is normal, especially on old carbs with lots of use. It's really only a problem if it gets beyond slight movement. Even then, it can be compensated for to some extent by adjusting the idle screws a tad richer. It won't affect off idle much, if at all (loose shaft).
 

AJ/FormS

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Some throttle shaft play is normal, especially on old carbs with lots of use. It's really only a problem if it gets beyond slight movement. Even then, it can be compensated for to some extent by adjusting the idle screws a tad richer. It won't affect off idle much, if at all (loose shaft).
What he said^^
I have never seen a carb so worn, that it would do what you say.
Much more likely is that the under-carb heater is not working correctly, or the heated air intake, or the idle-speed is too slow, closing the transfers, or the thermostat is not working right, or the accelerator pump system needs work, or and most common of all, like mentioned,
is a failing choke system.
All these systems are bandaides to a carb that is manufactured IMO, way too lean. You can fix that but it's usually easier to just restore the failed or failing systems.
BTW
the choke system, can be pretty dang fussy. The factory adjustments were set up for a new engine, back in the day, running on gas of the day, at or near sealevel. So here we are some 40 odd years later, and you got the sealevel part down pat...........
 

1337m4723

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About the vacuum amplifier. It's for the EGR system and isn't vital, unless you have emission tests in where you live. It boosts the weak vacuum signal from the ported EGR hose from the carb to a higher vacuum signal that can open the EGR valve. Of course, if it leaks internally, you'd have a vacuum leak. They don't appear to be listed anymore aftermarket but I do see them on Ebay quite often.

Check the choke operation. If it only happens on a cold engine, it's possible the choke is opening too soon, and quickly opening the throttle causes an extreme lean condition and engine "cough" or stall. I only say that since you said it's fine with the engine warm. Worth a look anyways.

Some throttle shaft play is normal, especially on old carbs with lots of use. It's really only a problem if it gets beyond slight movement. Even then, it can be compensated for to some extent by adjusting the idle screws a tad richer. It won't affect off idle much, if at all (loose shaft).

What he said^^
I have never seen a carb so worn, that it would do what you say.
Much more likely is that the under-carb heater is not working correctly, or the heated air intake, or the idle-speed is too slow, closing the transfers, or the thermostat is not working right, or the accelerator pump system needs work, or and most common of all, like mentioned,
is a failing choke system.
All these systems are bandaides to a carb that is manufactured IMO, way too lean. You can fix that but it's usually easier to just restore the failed or failing systems.
BTW
the choke system, can be pretty dang fussy. The factory adjustments were set up for a new engine, back in the day, running on gas of the day, at or near sealevel. So here we are some 40 odd years later, and you got the sealevel part down pat...........
Thank you all for your tipps!!

Yesterday I had the time to play around with a vacuum pump and a vacuum gauge.

So I think I found at least one faulty part: The distributor vacuum control leaks. I tested a new one and my old one in the car with the pump. The one I have built in cannot hold a vacuum.

Other faulty parts I found (I am assuming) is that someone "killed" the solenoid for the EGR-valve. The EGR valve is functioning with my hand vacuum pump and kills the engine in idle.
But when I set vacuum to the solenoid the EGR-valve is not moving. I need to varify this the next time I am at the car. (But that problem is not causing the trouble, since the EGR is closed..)

Next thing: The vacuum tee at the intake manifold was really worn out and broke when I removed one plug to connect my gauge... -.-"
Do you know where to find a replacement for the tee? (see the pictures) It doesn't need to be original... a suitable functioning port would make me happy.

All in all the vacuum only reaches about 15 psi in idle and does not hold the vacuum evenly. The needle is "dancing"...

IMG_20211123_201054.jpg


IMG_20211123_201210.jpg
 
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Camtron

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I have an original intake vacuum tree fitting I won’t be using again. You can have it for the flat rate shipping charges at USPS if you like.
 

69-

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Heh, we should have combined shipping to Hannover :)

As an easy fix, plug that brocken port with liquid metal, and use a T adapter in one of the other lines, if needed.

And I would replace all old vac lines.
 

AJ/FormS

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The distributor vacuum control leaks.
Is this the one on the distributor? If yes, it depends where you are checking from. >The Vacuum advance can itself should NOT leak vacuum, If it does, then it is worthless. But if you're pulling vacuum at the OSAC, that could be normal.
>The vacuum amplifier is a pneumatic relay. The yellow line is the signal generator. The manifold vacuum is the power supply. The orange hose sends manifold vacuum to the EGR,down the blue then white-traced hoses. But it is interrupted twice; first at the vacuum solenoid valve and second at the CCEGR thermo-vacuum valve. This means that three conditions have to be met to trigger the EGR;
1) the carb has to be opened far enough to open the port, and
2) the solenoid has to be energized (usually in Top gear), and
3) the coolant has to be above a certain minimum operating temperature.(usually 195*F)
To witness your system working, you will have to plumb a vacuum gauge close to the EGR valve in such a manner as you can see it from the driver's seat; then with the engine warm enough to open the factory rated thermostat, take it for a hiway run. When all three conditions are met, the EGR valve will open, and if it happens after say 30mph, you should not even notice it.
Your engine does neither need nor want EGR, but there is no harm in running it if your system is functioning properly.
The charcoal canister in the diagram is a full-time running device, but probably gets it's signal from venturi vacuum, or a port above the throttle blades, so that it does Not operate at idle.
I feel that your vacuum could be a little higher. Besides a vacuum leak, the biggest contributors to low vacuum, in order of probability, are;
1) a vacuum leak at one of the ports, or a exhaust getting into the intake underneath the carb
2) a high idle,
3) tight valves,
4) retarded timing,
5) very low or uneven compression pressure
6) a very high "wet" fuel level
The ones most likely to cause; "Idling is not really nice like the engine does not run "round"", are numbers 6,3 and 5, and on a 2bbl; imbalanced mixture screw adjustment. As you may notice, 5 and 3 are related
A wandering vacuum needle is usually showing an AirFuelRatio problem. Thus having a low Vacuum AND wandering needle, that does not clear up with mixture screw adjustment, AND does Not "round out", is usually pointing to a vacuum leak. And since slantys are known for the occasional intake to be leaking at one or more ports at the cylinder head; I would start by looking there.
And then, if you have a Solid Lifter engine, I would definitely go there next; followed by a compression test.
Good luck.
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Aspen500

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Never thought of valve adjustment if it's solid lifter. Going by your avatar photo, I'd guess it is solid. Too loose or too tight can cause all sorts of problems, especially the too tight way. That can keep the valves from fully closing when warm. Even if it isn't causing any obvious problems, it's always surprising how much smoother the engine runs when the adjustment is correct,,,,,,,and almost more importantly, the same for each cylinder.
 

1337m4723

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Hi guys! Thank you all for your kind replies :)

I'm sorry for not replying to the thread lately. Too much to do...

So, this weekend I had the opportunity to have a quick look at the engine and its problems. Now I'm sure the vacuum amplifier is broken, as it's not holding vacuum.

I installed a new vacuum control on the distributor as the old vacuum control was leaking.

Over the weekend, we checked several vacuum lines and found that in addition to the vacuum control at the distributor, the carburetor was also not creating a consistent vacuum at this vacuum port.
So this time the joke's on me...lol

We tried to adjust the ignition timing and discovered that my Aspen hasn't got a timing scale plate at the timing cover... this car is driving me nuts so hard xD. That's what a "character car" is about I guess.

So....

In November I ordered a new carburetor and a friend helped me install it. What can I say...the car runs really well. It idles very smoothly and doesn't stall. The acceleration has improved A LOT.
I think it was a bunch of different problems as you guys have told me. I'm really optimistic that the "severe" problems are taken care of now.

I have "killed" the EGR system because the vacuum amplifier does not hold the vacuum. I don't feel like fooling around with this system at the moment. I think at the next opportunity I will give it another try. But not right now.

So @AJ/FormS let me answer to your awesome list:
The Vacuum advance can itself should NOT leak vacuum, If it does, then it is worthless. But if you're pulling vacuum at the OSAC, that could be normal.
Yes, like I wrote above the advance leaked vauum. At my car the OSAC is equipped but it was not activated. The vacuum from the carburetor directly goes to the distributor. I guess a previous owner canceled the hoses... I am not really interested in causing more problems by re-install it :D... It should not be a problem I guess.
>The vacuum amplifier is a pneumatic relay. The yellow line is the signal generator. The manifold vacuum is the power supply. The orange hose sends manifold vacuum to the EGR,down the blue then white-traced hoses. But it is interrupted twice; first at the vacuum solenoid valve and second at the CCEGR thermo-vacuum valve. This means that three conditions have to be met to trigger the EGR;
1) the carb has to be opened far enough to open the port, and
2) the solenoid has to be energized (usually in Top gear), and
3) the coolant has to be above a certain minimum operating temperature.(usually 195*F)
To witness your system working, you will have to plumb a vacuum gauge close to the EGR valve in such a manner as you can see it from the driver's seat; then with the engine warm enough to open the factory rated thermostat, take it for a hiway run. When all three conditions are met, the EGR valve will open, and if it happens after say 30mph, you should not even notice it.
Your engine does neither need nor want EGR, but there is no harm in running it if your system is functioning properly.
The charcoal canister in the diagram is a full-time running device, but probably gets it's signal from venturi vacuum, or a port above the throttle blades, so that it does Not operate at idle.
Like I wrote aboce the amplifier won't hold a vacuum when I suck vacuum with my pump (through the black hose at the picture). Thank you for this detailed explanation. It is quite "hard" for a non-native speaker to comprehend all the terms. Your text was pretty much on point and helped me to understand other information from different websites.
1) a vacuum leak at one of the ports, or a exhaust getting into the intake underneath the carb
The carb is now a restored one. Maybe I change the EGR-valve next. I don't know if the one installed is maybe not completely closed. I "killed" the EGR-vacuum system right now, so it won't open up. But right now the engine runs pretty smooth. Not perfect, but the main issues are gone.
2) a high idle,
The new carb runs pretty slow and it sounds pretty smooth.
3) tight valves,
That is an open to do. When I have more time I will check the whole stuff around the valve cover.
4) retarded timing,
As I wrote in this post: There is no timing scale installed on this engine. Pretty messed up, in my opinion. But it runs fine now and the timing is not too bad. When I have more time, I will manually check the timing by looking for the UDC.
5) very low or uneven compression pressure
I will test the compression in the next steps also.
6) a very high "wet" fuel level
The new carb helped a lot I guess. When I find the time I will visit a garage and ask to check with an exhaust probe (Sorry if this term is mistaken).
The ones most likely to cause; "Idling is not really nice like the engine does not run "round"", are numbers 6,3 and 5, and on a 2bbl; imbalanced mixture screw adjustment. As you may notice, 5 and 3 are related
That sounds pretty plausible and understandable to me. I will check those issues next.
A wandering vacuum needle is usually showing an AirFuelRatio problem. Thus having a low Vacuum AND wandering needle, that does not clear up with mixture screw adjustment, AND does Not "round out", is usually pointing to a vacuum leak. And since slantys are known for the occasional intake to be leaking at one or more ports at the cylinder head; I would start by looking there.
The intake looks tight. No increase in RPM was observed when sprayed with brake cleaner. Since the vacuum looks pretty stable now, I suppose this chalice could pass me by. I really hope so.
And then, if you have a Solid Lifter engine, I would definitely go there next; followed by a compression test.
Yes sir! I will check those parts next time.

Never thought of valve adjustment if it's solid lifter. Going by your avatar photo, I'd guess it is solid. Too loose or too tight can cause all sorts of problems, especially the too tight way. That can keep the valves from fully closing when warm. Even if it isn't causing any obvious problems, it's always surprising how much smoother the engine runs when the adjustment is correct,,,,,,,and almost more importantly, the same for each cylinder.
Thank you for this advise! I will take a look.


So to all of you, thank you for your help and advice. I think the car is "OK" now. Not perfect, but it's OK for a drive. As I said, I will check your advice in the next steps. Maybe then the engine will run fully round.
 

Mikes5thAve

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I was going to say that a lot of your problems sounded carburetor related. It's good to hear replacing that made improvement.

On my 360 I couldn't get a lot of those egr parts anymore, plus I changed ignition and switched from 2bbl to 4bbl carb so a lot of it wouldn't work anyway. For emissions when it finally had to be tested I went back to the basic way and ran a vacuum hose from ported vacuum on carb to the heated egr switch (ccegr on the vacuum label I think) to egr valve.
 

armataz

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had a similar issue, turned out I had some leaking seals because of running ethenol, instead of gasoline. had the holley carb rebuilt using modern materials. and it runs fine now.
 

AJ/FormS

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As for the EGR valve, it is possible for them to be disconnected yet still operating at some unknown level. That goofy looking thing is just a vacuum-operated pintle valve. and if any carbon accumulates around the shaft, it is possible for it to hang open. When this happens you may have a hard to diagnose idle problem.
It is possible to test for this. on the engine.
The underside of that vacuum chamber is open to atmosphere, and the windows are large enough for you to get your fingers into. Sooo, what I do is poke my fingers thru the windows and lift the pintle up out of the orifice, and let it snap closed a few times. This usually dislodges the carbon and the idle improves. If you do this with the engine at idle speed, it may stall, so I put it up on the fast-idle cam. But the engine does not need to be running at this time. If it idles better, and more consistently afterwards, than you have succeeded.
If your engine does not have a timing tab on it, but does have a lil tin tube in the vicinity of where one would usually look for it, that is where the factory would have dropped a probe into, to check the timing. You might be able to shine a light in there but I have never had any success at that.
You can make a mark anywhere that is convenient. You will need one anyway to properly set the valves.
All you gotta do is put the engine at #1TDC, on the compression stroke using a piston-stop, and once this is done you can make a mark on the balancer and a matching mark on the timing-cover directly in line with it, ANYWHERE that is convenient for shining the strobe to. After this is done, you have to use a dial-back timing lite OR, since you will need index marks to set your valves, you can do one of the following;
1) install a timing tape, which is a calibrated 360 degree stick-on tape, or
2) repeat the TDC marking but for the next two cylinders following in the firing order. or
3) FABO has a procedure for "hillbilly timing", in the which you make your own marks by using a ruler or cloth tape.
Any method will work, but the first is the most accurate and usually the easiest. The last time I bought a tape, they were well worth the 7bucks.

I gotta warn you about timing;
At idle;
your engine will like a lot of timing; to a point, the more you give her, the smoother it will idle. She may like 20 to 30 degrees! But you MUST NOT drive it like that as the engine will likely begin detonating nearly right away. If not, then as soon as the engine sees a load. Detonation must be avoided no matter what, because it can only lead to broken parts.
Bottom line is to forget timing it by ear.
Furthermore; the power timing MUST be limited to below the detonation threshold. PowerTiming is; the Max timing that your Distributor is able to achieve at some as yet undetermind rpm, PLUS, the idle timing. So if the engine detonates at over 30degrees PowerTiming at say 3000 rpm then that is all you can give it. If that means your idle-timing is Zero, then that is all you can run...... until you "reprogram" your distributor. Detonation must be avoided.
Happy HotRodding
 

BudW

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Detonation must be avoided.
I would rephrase that to "Detonation MUST be avoided, at all costs!".

Every time you hear a "ping" or a clatter noise, it is from an secondary ignition flame front (igniting before spark plug does) and the effect to engine is the same as taking a hammer and hitting the aluminum piston top. This happens each and every time a ping or clatter noise occurs.
If you keep hitting something long enough with a hammer, something will eventually break.

Examples:
detonation damage 1.jpg

Each pit is one ping
detonation damage 3.jpg


Keep it going long enough and this happens:
detonation damage 4.jpg

This piston is still in the cylinder.
detonation damage 5.jpg


The same kind of damage can occur to aluminum cylinder heads (which not not an issue on stock FMJ's)

If you hear an engine pinging or rattling - just stop and adjust the ignition timing.
Your engine (and your wallet) will thank you.
BudW
 
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